Kepler-730 c
Astrophysical Synthesis & Habitability Characterization
Kepler-730 c is a confirmed super-earth exoplanet orbiting the star Kepler-730, located approximately 6311.2 light-years (1935.04 parsecs) from the Solar System. First announced in 2018 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0104% across the stellar disk), this world measures 1.569 Earth radii and has a measured mass of 3.09 Earth masses. Combining its mass and radius yields a mean bulk density of 4.41 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.26 g⊕ (12.36 m/s²), and an escape velocity of 15.7 km/s.
In its orbital architecture around Kepler-730, Kepler-730 c completes one full revolution every 2.852 Earth days at a semi-major axis of 0.03997 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 152.5 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1607 K (+1334°C / +2433°F) and receiving 903.77 S⊕ (~1,230,031 W/m²), Kepler-730 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-730 is classified as a stellar host with an effective photospheric temperature of 5,620 K, a radius of 1.411 R☉, a mass of 1.047 M☉, an estimated bolometric luminosity of 1.782 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.5 Gyr and a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, Kepler-730 shines at apparent V-band magnitude 15.782 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-730 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-730 c sharing its stellar neighborhood alongside Kepler-730 b.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Kepler-730 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,620 K |
| Stellar Radius | 1.4110 R☉ |
| Stellar Mass | 1.0470 M☉ |
| Bolometric Luminosity | 1.782 L☉ |
| Metallicity [Fe/H] | 0.210 dex |
| Stellar Age | 9.500 Gyr |
| Apparent Magnitude | V: 15.782 · G: 15.611 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.039970 AU |
| Orbital Period | 2.852 days |
| Mean Orbital Velocity | 152.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 83.8100° |
| Mean Bulk Density | 4.41 g/cm³ (15.7 km/s vesc) |
| Insolation Flux | 903.7700 S⊕ (~1,230,031 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 6311.200 LY (1935.040 pc) |